The approaches described in this section could be pursued, but are not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, the approaches described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
Computer networks generally comprise infrastructure devices or elements, such as routers and switches, and end station devices, such as servers, workstations, personal computers, handheld computers, and printers. The introduction of Application Oriented Networking (AON) devices from Cisco Systems, Inc., San Jose, Calif., has provided more flexibility in how network infrastructure elements process application-layer messages (that is, messages of OSI Layer 5, 6, and above).
While AON devices provide implementations of many application protocols and standards, many business enterprises have other infrastructure devices or end station devices that use legacy code or custom code and proprietary formats or protocols that need to be supported. In other cases, the AON devices may omit support for a particular database type or other standard scheme that the enterprises need. In past approaches, extension of AON device capabilities has required re-implementing an entire code module. For example, the AON Authentication bladelet provides support for standard LDAP and Kerberos-based authentication, but if an enterprise wants to use Netegrity SiteMinder for authentication, the enterprise is required to re-implement the entire authentication bladelet using custom code.
In past approaches, extending the behavior of a programmatic capability requires the code implementing that capability to be exposed to a customer of the networking vendor that is facilitating the extension. For example, code developed using the JAVA programming language typically provides interfaces of abstract classes that users extend to customize the behavior of the JAVA program.